NGK Iridium IX Observations

[wantin150]

My 03 Toyota Matrix XRS came with Denso Iridium plugs good for "100k". I replaced them at 50k with NGK Iridium IX. Factory spec is .043. IX plugs come set at .044 which was checked with a gauge prior to installation. I recently hit 98k and changed the plugs. The gap had eroded to .060+. Why? The IX should be a 100k plug and eroded more than the OEM plugs at 50k (checked upon removal). I replaced with OEM plugs for grins and giggles (at a price of course).

Why would the gap erode that much over such a "short" period of time?

 

[mikered30]

How high can that XRS rev?

 

[Chris Meutsch]

I think they shudder when changed before their 100k limits and get a bigger gap.

Just kidding.

Did performance suffer or did you change them because you simply wanted to?

 

[wantin150]

At 8250, you hit the limiter. I will hit it occasionally but not often at all. "Lift" kicks in at 6,000 which I will hit getting on the interstate at times. Sucks too much of the premium fuel required though to do it too often.

 

[brandini]

That is not a 100k plug no matter what it says on the box, it's probably a 40-60k plug. There is an upper level iridium plug that will last 100k but it's a few bucks more.

 

[xBa380]

The IX Iridium's are half the expected life as the slightly more expensive Laser Iridium's (OE Plugs).

I accidentally got the IX when I did my girlfriends plugs about 45K miles ago and just replaced them with the laser ones. I read somewhere about the life of the plugs but don't remember where.

 

[dparm]

Was it a single-electrode? Usually the multi-electrode are good for 100k.

Even so, I change my once a year. Cheap insurance.

 

[StevieC]

In his application because he has coil overs and doesn't have a "spark waste system" he can run the single electrode for that long.

 

[StevieC]

Originally Posted By: wantin150
My 03 Toyota Matrix XRS came with Denso Iridium plugs good for "100k". I replaced them at 50k with NGK Iridium IX. Factory spec is .043. IX plugs come set at .044 which was checked with a gauge prior to installation. I recently hit 98k and changed the plugs. The gap had eroded to .060+. Why? The IX should be a 100k plug and eroded more than the OEM plugs at 50k (checked upon removal). I replaced with OEM plugs for grins and giggles (at a price of course).

Why would the gap erode that much over such a "short" period of time?
Not sure... Do you redline alot? Is the engine running hot or too lean? Any harsh fuel additives?

 

[The Critic]

Originally Posted By: StevieC
In his application because he has coil overs and doesn't have a "spark waste system" he can run the single electrode for that long.

Not necessarily, as the lack of a plat pad on the ground electrode will still reduce life. That's why all OE platinum and iridium plugs have the plat pad on the ground electrode, even if it is not a waste spark system.

 

[StevieC]

I understood that it wasn't necessary in a non-waste spark system because it's only firing the spark 1 out of 4 strokes so the plug has a chance to cool by not being fired more than that.

The platinum plated ground electrode makes sense in a waste spark system where this doesn't happen.

Even a slightly cooler running plug would help the wear factor in both cases without affecting emission/performance too much as long as you don't go crazy.

Steve

 

[JHZR2]

different alloy? different electrode setup? Did you go back to OE for the next 50k to compare?

 

[JustinH]

Honestly, I bet that the car would have gotten to 100k on the OEM plugs. Not optimal performance at all, but it would have gotten there.

I didn't know that toyota did anything different to the motor in the XRS, but after some reading it sounds like a neat little car. Super high compression engine!

 

[OVERKILL]

Originally Posted By: The Critic
Originally Posted By: StevieC
In his application because he has coil overs and doesn't have a "spark waste system" he can run the single electrode for that long.

Not necessarily, as the lack of a plat pad on the ground electrode will still reduce life. That's why all OE platinum and iridium plugs have the plat pad on the ground electrode, even if it is not a waste spark system.


My Ford ones didn't. And they lasted 200,000Km.

I think some plugs are just "better" than others. And likely what the OP is experiencing.

 

[StevieC]

Maybe it's NGK quality going down the tube, just thought of this now... I run NGK Iridium's in my Santa Fe and the first set lasted to 100K (60K miles) and looked like brand new but this second set didn't make it to 80K and 1 was breaking down so I replaced them all.

 

[PandaBear]

The way dielectric break down (spark) work is the firing voltage is inversely proportional to the surface area of the firing point. So if the IX plug has sharper tip, for the same voltage it will fire even if the gap is wider than OEM plug that has not so sharp tip.

I wouldn't worry about it.

 

[Lethal1ty17]

Iridium IX = 60k miles

Laser Iridium = 100k miles

i ran my IX's hard for 25-30k in my car, stock gap on them is .043 i beleive, after almost 30k they hadnt even eroded to .045

 

[JustinH]

Do you guys notice any difference in performance by using these iridium plugs over say their GP line of plugs?

I have been very happy using the GP plugs in a couple ecotec cars. These plugs are $2.19 each, as opposed to 7 or 10 dollars.

 

[StevieC]

My SUV came with NGK and they run great on NGK. We have crazy weather in my part of Canada from extreme heat to really cold and they put up with it all. Car starts and runs very smooth and the performance is excellent. I would highly recommend NGK's

 

[bepperb]

The IX doesn't have a platinum pad on the electrode, the Laser series does. You get what you pay for.